net.sourceforge.phpeclipse.ui/src/net/sourceforge/phpdt/internal/ui/viewsupport/ResourceToItemsMapper.java

   1 /*******************************************************************************
   2  * Copyright (c) 2000, 2004 IBM Corporation and others.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Common Public License v1.0
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/cpl-v10.html
   7  *
   8  * Contributors:
   9  *     IBM Corporation - initial API and implementation
  10  *******************************************************************************/
  11 package net.sourceforge.phpdt.internal.ui.viewsupport;
  12
  13 import java.util.ArrayList;
  14 import java.util.HashMap;
  15 import java.util.List;
  16 import java.util.Stack;
  17
  18 import net.sourceforge.phpdt.core.ICompilationUnit;
  19 import net.sourceforge.phpdt.core.IJavaElement;
  20
  21 import org.eclipse.core.resources.IResource;
  22 import org.eclipse.jface.viewers.ContentViewer;
  23 import org.eclipse.jface.viewers.ILabelProvider;
  24 import org.eclipse.jface.viewers.IViewerLabelProvider;
  25 import org.eclipse.jface.viewers.ViewerLabel;
  26 import org.eclipse.swt.graphics.Image;
  27 import org.eclipse.swt.widgets.Item;
  28
  29 /**
  30  * Helper class for updating error markers and other decorators that work on
  31  * resources. Items are mapped to their element's underlying resource. Method
  32  * <code>resourceChanged</code> updates all items that are affected from the
  33  * changed elements.
  34  */
  35 public class ResourceToItemsMapper {
  36
  37         private static final int NUMBER_LIST_REUSE = 10;
  38
  39         // map from resource to item
  40         private HashMap fResourceToItem;
  41
  42         private Stack fReuseLists;
  43
  44         private ContentViewer fContentViewer;
  45
  46         public ResourceToItemsMapper(ContentViewer viewer) {
  47                 fResourceToItem = new HashMap();
  48                 fReuseLists = new Stack();
  49
  50                 fContentViewer = viewer;
  51         }
  52
  53         /**
  54          * Must be called from the UI thread.
  55          */
  56         public void resourceChanged(IResource changedResource) {
  57                 Object obj = fResourceToItem.get(changedResource);
  58                 if (obj == null) {
  59                         // not mapped
  60                 } else if (obj instanceof Item) {
  61                         updateItem((Item) obj);
  62                 } else { // List of Items
  63                         List list = (List) obj;
  64                         for (int k = 0; k < list.size(); k++) {
  65                                 updateItem((Item) list.get(k));
  66                         }
  67                 }
  68         }
  69
  70         private void updateItem(Item item) {
  71                 if (!item.isDisposed()) { // defensive code
  72                         ILabelProvider lprovider = (ILabelProvider) fContentViewer
  73                                         .getLabelProvider();
  74
  75                         Object data = item.getData();
  76
  77                         // If it is an IItemLabelProvider than short circuit: patch Tod (bug
  78                         // 55012)
  79                         if (lprovider instanceof IViewerLabelProvider) {
  80                                 IViewerLabelProvider provider = (IViewerLabelProvider) lprovider;
  81
  82                                 ViewerLabel updateLabel = new ViewerLabel(item.getText(), item
  83                                                 .getImage());
  84                                 provider.updateLabel(updateLabel, data);
  85
  86                                 if (updateLabel.hasNewImage()) {
  87                                         item.setImage(updateLabel.getImage());
  88                                 }
  89                                 if (updateLabel.hasNewText()) {
  90                                         item.setText(updateLabel.getText());
  91                                 }
  92                         } else {
  93                                 Image oldImage = item.getImage();
  94                                 Image image = lprovider.getImage(data);
  95                                 if (image != null && !image.equals(oldImage)) {
  96                                         item.setImage(image);
  97                                 }
  98                                 String oldText = item.getText();
  99                                 String text = lprovider.getText(data);
 100                                 if (text != null && !text.equals(oldText)) {
 101                                         item.setText(text);
 102                                 }
 103                         }
 104                 }
 105         }
 106
 107         /**
 108          * Adds a new item to the map.
 109          *
 110          * @param element
 111          *            Element to map
 112          * @param item
 113          *            The item used for the element
 114          */
 115         public void addToMap(Object element, Item item) {
 116                 IResource resource = getCorrespondingResource(element);
 117                 if (resource != null) {
 118                         Object existingMapping = fResourceToItem.get(resource);
 119                         if (existingMapping == null) {
 120                                 fResourceToItem.put(resource, item);
 121                         } else if (existingMapping instanceof Item) {
 122                                 if (existingMapping != item) {
 123                                         List list = getNewList();
 124                                         list.add(existingMapping);
 125                                         list.add(item);
 126                                         fResourceToItem.put(resource, list);
 127                                 }
 128                         } else { // List
 129                                 List list = (List) existingMapping;
 130                                 if (!list.contains(item)) {
 131                                         list.add(item);
 132                                 }
 133                         }
 134                 }
 135         }
 136
 137         /**
 138          * Removes an element from the map.
 139          */
 140         public void removeFromMap(Object element, Item item) {
 141                 IResource resource = getCorrespondingResource(element);
 142                 if (resource != null) {
 143                         Object existingMapping = fResourceToItem.get(resource);
 144                         if (existingMapping == null) {
 145                                 return;
 146                         } else if (existingMapping instanceof Item) {
 147                                 fResourceToItem.remove(resource);
 148                         } else { // List
 149                                 List list = (List) existingMapping;
 150                                 list.remove(item);
 151                                 if (list.isEmpty()) {
 152                                         fResourceToItem.remove(list);
 153                                         releaseList(list);
 154                                 }
 155                         }
 156                 }
 157         }
 158
 159         private List getNewList() {
 160                 if (!fReuseLists.isEmpty()) {
 161                         return (List) fReuseLists.pop();
 162                 }
 163                 return new ArrayList(2);
 164         }
 165
 166         private void releaseList(List list) {
 167                 if (fReuseLists.size() < NUMBER_LIST_REUSE) {
 168                         fReuseLists.push(list);
 169                 }
 170         }
 171
 172         /**
 173          * Clears the map.
 174          */
 175         public void clearMap() {
 176                 fResourceToItem.clear();
 177         }
 178
 179         /**
 180          * Tests if the map is empty
 181          */
 182         public boolean isEmpty() {
 183                 return fResourceToItem.isEmpty();
 184         }
 185
 186         /**
 187          * Method that decides which elements can have error markers Returns null if
 188          * an element can not have error markers.
 189          */
 190         private static IResource getCorrespondingResource(Object element) {
 191                 if (element instanceof IJavaElement) {
 192                         IJavaElement elem = (IJavaElement) element;
 193                         if (!elem.isReadOnly()) { // only modifieable elements can get
 194                                                                                 // error ticks
 195                                 IResource res = elem.getResource();
 196                                 if (res == null) {
 197                                         ICompilationUnit cu = (ICompilationUnit) elem
 198                                                         .getAncestor(IJavaElement.COMPILATION_UNIT);
 199                                         if (cu != null) {
 200                                                 // elements in compilation units are mapped to the
 201                                                 // underlying resource of the original cu
 202                                                 res = cu.getResource();
 203                                         }
 204                                 }
 205                                 return res;
 206                         }
 207                         return null;
 208                 } else if (element instanceof IResource) {
 209                         return (IResource) element;
 210                 }
 211                 return null;
 212         }
 213
 214 }